Josefina is a landlocked municipality in the coastal province of Zamboanga del Sur.

The municipality has a land area of 56.35 square kilometers or 21.76 square miles which constitutes 1.26% of Zamboanga del Sur’s total area. Its population as determined by the 2020 Census was 12,205. This represented 1.16% of the total population of Zamboanga del Sur province, or 0.31% of the overall population of the Zamboanga Peninsula region. Based on these figures, the population density is computed at 217 inhabitants per square kilometer or 561 inhabitants per square mile.